1. Field of the Invention
The invention relates in general to electrical transformers, and more specifically to electrical transformers in which the vector sum of the magnetic flux produced in the magnetic core creates an oscillating induction vector.
2. Description of the Prior Art
Co-pending Application Ser. No. 607,852, filed May 7, 1984, entitled "Low Core Loss Rotating Flux Transformer", now U.S. Pat. No. 4,595,843, which is assigned to the same assignee as the present application, discloses a transformer construction in which a rotating induction vector is produced in the entire magnetic core. The magnetic core is in the form of a torus, with both toroidal and poloidal windings generating phase displaced alternating flux which is added vectorially to create a rotating induction vector. By providing sufficient exciting current to produce a saturated rotating induction vector, the magnetic domains disappear and hysteresis losses are reduced to zero. The anomalous component of the eddy current losses is also eliminated at saturation. When the magnetic core is constructed of an amorphous alloy, which is nominally about 1 mil thick, a magnetic core with unusually low core losses is produced, as the elimination of the anomalous component of the eddy current losses at saturated further reduces the already low eddy current losses of an amorphous magnetic core. Application Ser. No. 607,852, is hereby incorporated into the Specification of the present application by reference.
The rotating flux transformer of the co-pending application while having many advantages, has a disadvantage with respect to how it handles an overvoltage condition on the primary winding, as a higher than normal primary voltage does not produce much more useful flux than already present. The primary current, during an overvoltage condition will thus increase, as there is very little back induced voltage to oppose it. Thus, a higher than normal primary voltage can only be accommodated by an increased IR drop.
The rotating flux transformer is also basically a two-phase, or a three-phase transformer.